unit Unit1;interfaceusesWindows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,Dialogs, StdCtrls, ExtCtrls;typeTMyShape = class(TShape)protectedprocedure CMMouseenter(var Message: TMessage); message CM_MOUSEENTER;procedure CMMouseleave(var Message: TMessage); message CM_MOUSELEAVE;end;TForm1 = class(TForm)Panel1: TPanel;Button1: TButton;Button2: TButton;procedure Button1Click(Sender: TObject);procedure Button2Click(Sender: TObject);end;varForm1: TForm1;implementation{$R *.dfm}procedure TForm1.Button1Click(Sender: TObject);
constW = 50;H = 50;
varshape: TMyShape;
beginshape := TMyShape.Create(Self);shape.Parent := Panel1;shape.Width := W;shape.Height := H;Randomize;shape.Left := Random(Panel1.ClientWidth - W);shape.Top := Random(Panel1.ClientHeight - H);shape.Brush.Color := Random($FFFFFF);
end;procedure TForm1.Button2Click(Sender: TObject);
vari: Integer;
beginif Panel1.ControlCount = 0 then Exit;Randomize;i := Random(Panel1.ControlCount - 1);Panel1.Controls[i].Free;
end;{ TMyShape }procedure TMyShape.CMMouseenter(var Message: TMessage);
consts = '当前 %s 的颜色值是: %.6x';
varWCtrl: TWinControl;
beginWCtrl := Parent;while WCtrl.HasParent do WCtrl := WCtrl.Parent;if WCtrl is TForm then TForm(WCtrl).Caption := Format(s, [ClassName,Brush.Color]);inherited;
end;procedure TMyShape.CMMouseleave(var Message: TMessage);
consts = 'Form1';
varWCtrl: TWinControl;
beginWCtrl := Parent;while WCtrl.HasParent do WCtrl := WCtrl.Parent;if WCtrl is TForm then TForm(WCtrl).Caption := s;inherited;
end;end.

窗体文件:

object Form1: TForm1Left = 0Top = 0Caption = 'Form1'ClientHeight = 212ClientWidth = 395Color = clBtnFaceFont.Charset = DEFAULT_CHARSETFont.Color = clWindowTextFont.Height = -11Font.Name = 'Tahoma'Font.Style = []OldCreateOrder = FalsePixelsPerInch = 96TextHeight = 13object Panel1: TPanelLeft = 8Top = 8Width = 297Height = 193Caption = 'Panel1'TabOrder = 0endobject Button1: TButtonLeft = 311Top = 40Width = 75Height = 25Caption = #28155#21152TabOrder = 1OnClick = Button1Clickendobject Button2: TButtonLeft = 311Top = 85Width = 75Height = 25Caption = #38543#26426#21024#38500TabOrder = 2OnClick = Button2Clickend
end